Stem cell therapy side effects & risks at clinics – The Niche

By daniellenierenberg

What are possible side effects of stem cell therapy ? Patients often reach out to ask about such risks They usually refer to unproven stem cell clinics.

Todays post addresses the scope of stem cell therapy side effects and risks based on available hard data. Its also important to discuss possible unknown risks.

In this post I am focusing on the risks primarily associated with unproven stem cell clinics. Not for established methods like bone marrow transplantation, which have their own risks including the shared one of infection.

Recent publications in journals have helped clarify risks. This literature includes a study by my UC Davis colleague Gerhard Bauer and a special report by The Pew Charitable Trust. Gerhards paper presents the types of side effects that appear more common after people go to stem cell clinics. After closely following this area for a decade I was familiar with many of the examples of problems.

One of the highest profile examples of bad outcomes was the case where three people lost their vision due to stem cells injected by a clinic.

I have included a YouTube video below on stem cell therapy side effects as well.

Why do stem cells pose risks?

One major reason is that stem cells are uniquely powerful cells.

By definition they can both make more of themselves and turn into at least one other kind of specialized cells. This latter attribute is called potency and the process of becoming other cells is called differentiation. The ability to make more of themselves is called self-renewal.

The most powerful stem cells are totipotent stem cells that can literally make any kind of differentiated cell. The fertilized human egg is the best example of a cell having totipotency. The first few cell divisions after that retain the totipotency. Next in the power lineup are pluripotent stem cells including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). These cells are not directly used in therapies.

Adult stem cells are multipotent, which means they can make just a few types of specialized cells.

What is the best type of stem cell? The best type of stem cell depends on the condition that is trying to be treated and may not be the most powerful.

In any case, the power of stem cells is one reason they also pose risks along with mishandling that can cause infections. Stem cells are not always easy to control and misdirected power can do harm.

Let me explain and start with the side effect that seems most concerning to most people but is probably the rarest. Tumor formation.

If someone injects a patient with stem cells, its possible that the self-renewal power of stem cells just wont get shut off. In that scenario, the stem cells could drive the formation of a tumor.

Why wouldnt a transplanted stem cell always eventually hit the brakes on self-renewal? It could be that the stem cell has one or more mutations. For any stem cells grown in a lab, within the population of millions of cells in a dish, there are going to be at least a few with mutations that crop up. Thats just the way it goes with growing cells in a lab. The longer you grow them the more mutations they will have on average.

Even stem cells not grown in the lab have the same spectrum of mutations as the person they were isolated from. It may seem odd to think about, but we all have some mutations.

Research suggests it takes more than one cell with cancer-causing potential to make a tumor in experiments in the lab, but in actual people, we just dont know. Many cancers may arise from one stem cell gone awry. If a clinic injects 100 or 500 million cells, a one-in-a-million rate of potentially dangerous cells means that 100-500 such risky cells end up in the patient. The risk of getting an actual tumor may still be low but I wouldnt take those odds.

The encouraging news here is that the incidence of tumors in stem cell clinic customers, particularly in the U.S., appears extremely low.

The odds of getting a tumor are far lower for cells never grown in a lab but its still possible. Oddly, receiving someone elses stem cells (we call this allogeneic) might pose a lower cancer risk because your immune system is going to see those cells as foreign from the start. Itll reject them. Still, an immunocompromised state could play a role.

Some stem cells, especially those with mutations, might be able to somewhat fly under the radar of the immune system to some extent. This could allow them to grow into a tumor.

The Pew report does a nice job of summarizing risks and there are several reports of tumors.

The possibility of infections after stem cell injections is another risk that is often discussed. Infections from injections of stem cells or other biologics are probably the most common type of side effect. Bacteria can sometimes already be in the product that is injected. Or germs can be introduced by poor injection or preparation methods by the one doing the procedure.

The distributor Liveyon had a product contaminated with bacteria that sickened at least a dozen people who were hospitalized. Some of them ended up in the ICU. A few may even have permanent issues.

Infection risk usually does not arise from the cells themselves.

Another risk is the potential for blood clots.

In the case of adipose biologics life SVF, they mostly consist of a mixture of a dozen or so other kinds of cells found in fat. Fat cells just live in fat so they arent supposed to be floating around in your blood. As a result, after IV injection, many fat cells are thought to get killed right away by the immune system or the microenvironment. While in the blood, fat and other stromal-type cells, whether dead or alive, may catalyze clot formation, which is dangerous.

Some of these cells end up landing in the lungs. There many cells are probably being killed and theres also risk of blood clot formation.

Unproven clinics mainly sell MSCs.

MSCs could have some powerful uses in medicine. I can already see a few rigorous clinical trials that look exciting.

However, the way some unproven clinics use MSCs can be highly risky.

Such cells just shouldnt be injected willy-nilly into dozens of places in patients including into peoples eyes. Further, what are called MSCs by some unproven clinics may also not meet even basic lab standards and may not have the potential of other MSC preps. Some such clinic preps are likely just fibroblasts or mostly dead cells.

MSCs produced in a rigorous manner in clean labs by experienced teams are likely to be a far superior product than that typically made by just any strip mall clinic. I dont endorse any cell therapy clinic selling MSCs at this time, but some are doing far better than others. They do research and publish papers.

Properly conducted injections of unmodified, high quality MSC-type cells or marrow cells into joints or for other orthopedic conditions by qualified providers in theory should pose almost zero risk of pulmonary emboli or cancer. Clinics using excellent procedures and cell products also should pose a very low risk of infection, a risk more similar to getting medical procedures in general even unrelated to stem cells.

Overall, Im not sure I believe such MSCs even from the best clinics can provide lasting benefit for diverse orthopedic conditions, but the overall risks associated with them should be quite low there relatively speaking.

Patients have also asked me about other potential risks of cell injections.

I wrote a post about possible graft versus host disease in stem cell recipients. This would only happen in people receiving someone elses stem cells and probably only with IV administration. Its not clear if GvHD is something that happens to patients after going to clinics selling allogeneic cells. With no immunosuppression, it should be highly unlikely.

Beyond outright tumor formation, it is also possible that stem cells may become an undesired or even dangerous tissue type that isnt technically an actual tumor. The example that comes to mind is the practice mentioned earlier of some clinics injecting fat cells into peoples eyes. What seems to have happened in some cases is that the mesenchymal cells (MSCs) or other cells like fibroblasts that were injected turned into scar tissue, which caused retinal detachment.

In addition, we have seen indications that patients getting IV infusions of stem cells might be at some risk for heart attacks. Perhaps via clot formation. For example, read this piece: Cellular Performance Institute death.

One of the challenges is that it can be difficult to figure out if heart attacks or other outcomes were linked to the actual stem cell procedures or just incidental. Many patients getting stem cells may already be at higher risks for these issues. In any particular case, one can ask: was the cell infusion linked to the death? Im not sure we could ever know. Such outcomes should be carefully tracked and analyzed. One challenge is that adverse events at hundreds of unproven clinics may never be reported or otherwise come to light.

Specific routes of administration may pose unique risks as well. For instance, intranasal stem cells are getting popular with some unproven clinics and could lead to cells or other material ending up in the brain. Intranasal delivery of stem cells could have real promise such as for treating brain conditions, but you need rigorous clinical data to back that up. You need to work with the FDA and send them data. Clinics without such data are already selling the procedure.

Other products in the regenerative sphere that are not stem cells may be risky as well for various reasons. For instance, an exosome product harmed quite a few people in Nebraska. Some problems may relate to product contamination. Here again, exosomes may have promise for some conditions but should not be sold already as therapies at this time.

Finally, stem cells and other cell therapies also pose unknown risks because of their newness and power.

We also just dont have long-term follow-up data to have a clear sense of all major risks after people go to clinics.

In general, so much depends on collecting good data before trying to make money form vulnerable patients.

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Stem cell therapy side effects & risks at clinics - The Niche